Kia van trouble - transmission.
November 10, 2014 6:27 PM   Subscribe

2011 Kia Sedona will sometimes have this funky problem wherein there is a significant loss of power. That is, I can floor the gas pedal and it's pretty unresponsive. Oddly, the digital instrument panel indicator that usually shows what gear it is in (or D for drive) doesn't show anything at all for the gear (the panel is otherwise lit up normally) when this problem is present.

It's a come and go problem that has never been present when at the dealer. This post probably ought to be in a Kia forum somewhere but as specific as the problem is, I'm hoping someone else has experienced just this thing and can suggest a fix.
posted by whatisish to Travel & Transportation (13 answers total) 1 user marked this as a favorite
 
Do the engine revs rise when it seems to lose power? Like it was accelerating but the car doesn't go any faster? Or is the *engine* non-responsive to your foot going down.

Is there any jolt when it goes 'back to normal'? What happens to make it go back to normal after these episodes - can you recreate it or do you just have to wait?

It could be that the car is low on transmission oil (or some other root cause) and the drive is slipping (in which case the revs will rise but the car will not accelerate at a matching rate. This would be consistent with the gear indicator issue. Or it could be that the engine is losing power, in which case it will sound 'flat' and the revs will rise slower than usual and the car accelerate very slowly (or not at all). In teh second case, the gear selector reading is a red herring potentially.

So questions:

1: When this happens, do the engine revs rise as normal or faster than normal? Does the engine make noise but the car doesn't go faster?

2: Is there any clonk or jerk after this point as things return to normal?

If none of the above, describe more precisely what you do, what happens, what you expect to happen and talk us through it. Trying to get people to describe things in a way that makes sense is often hard on here as people use different terminology for things.
posted by Brockles at 6:44 PM on November 10, 2014 [1 favorite]


Oook. I'm no van or Kia expert, so take my words with a severe grain of salt, but your description is quite similar to the two times I've had, in other makes and models (one van, one not) a transmission in the process of going out. And we stumbled along that way until one day, it went.

Good luck.
posted by stormyteal at 6:46 PM on November 10, 2014


Response by poster: 1. The engine doesn't ever rev. The speed will slowly increase - up to even highway speed but I can't feel the gears change. They must though because the rpms always seem appropriate. It's just really unresponsive to the gas pedal.

2. No clonk or jerk to get back to normal. If I stop, turn it off, and restart it, if the gear indicator is present on the dash, it'll be fine. If it is absent, there are problems. That's my tell. It doesn't start and/or stop working while running.

37000 miles and the fluids are ok.
posted by whatisish at 6:58 PM on November 10, 2014


Best answer: There is a possibility that the car is on limp mode because it is losing either the gear sensor input or something upon which the gear sensor depends? Rebooting the system to fix it means that a sensor (or the control box that controls whatever that sensor does) is skewy, I suspect.

That'd fit with the engine running on very reduced power (automotive 'safe mode' basically) and a reboot can make the mismatch go away. I'd say a sensor is going down (relatively cheap maybe) or a control box is going down (...not so cheap). Or more complicated (wiring loom or earth issue) which hopefully it isn't, as that can be a drama.

Have you given that exact feedback to the garage? If you have an intermittent issue and you can either reliably repeat the symptoms (ideally) or at the very least repeat the fix, then you have a fighting chance. I'm not familiar with the electronics on a Kia, but I have had a throttle sensor failure that did roughly the same thing (although it produced a written 'limp mode' warning on the dash) so some kind of sensor going down or the ECU losing track of it in some way would be what I'd look for.

If at all possible and you can get one of those bluetooth scanners (I have one for my iphone that was about $60) you can scan the fault codes through the OBD2 port next time it does it. It will likely throw a code. Presumably the dealer scanned for codes (please tell me they did!) and there were none because they are clearing when you reset the ignition? So either repeat the whole process like you have with us, or try and scan the codes yourself next time it does it.
posted by Brockles at 7:54 PM on November 10, 2014


Response by poster: Thanks for your time Brockles. I had Auto Zone check for codes after a same day episode but none were present. Then again, it happened to be working then. Given that it may not occur again for weeks, I may just have to wait. I'll shoot you a PM if/when I figure it out (always nice to hear how a puzzle is solved, right?). I like the idea of a sensor going bad though. Thanks again.
posted by whatisish at 8:22 PM on November 10, 2014


This sounds suspiciously like a clogged fuel filter problem I once had. The power loss would come and go, but got steadily worse until I figured it out.
posted by dws at 9:08 PM on November 10, 2014


It also reminded me of a fuel filter issue/fuel line blockage that I had once, but that was also accompanied by a bad smell. I also don't remember it affecting any of the displays.

Have you ever let the fuel get very low before filling it up?
posted by kinddieserzeit at 5:08 AM on November 11, 2014


It may be that this is a fuel obstruction - odd that the gear indicator seems to be aligned to the presence of the issue, but it may be coincidental or some other form of indication I don't know about.

If you haven't changed the Fuel filter since the car was new (or it hasn't been by the previous owner) then changing it now is a good idea anyway.
posted by Brockles at 6:10 AM on November 11, 2014


(wife of whatisish here).

kinddieserzeit - last week I let the fuel get pretty low and it wouldn't start. No clicking, no indication of it turning over at all. Then, a few hours later, I tried again and it started right up.

Brockles: I don't believe the filter has been changed.
posted by Sassyfras at 6:23 AM on November 11, 2014


I can't think of a scenario where a blocked fuel line or filter would prevent the car from turning over (whether or not it started) so I am back to thinking this is some sensor or control unit failing that is preventing a start. Likely candidates are:

Crank sensor
Throttle sensor
Cam sensor (? if it has one)
Maybe transmission speed or gear selected sensor (so it can't tell what gear it is in when running so limits revs, and can't tell if it is in park/neutral when not running so prevents start).

There are others, but that's where my gut feeling is taking me, based on the information presented and guessing over the internet. Is there not check engine light on? No ECU warning light? No other unusual lights on the dash that stay on that don't normally?
posted by Brockles at 9:29 AM on November 11, 2014


Response by poster: Nope. No check engine light or other dash indication when there are problems. I might just have the fuel filter changed but when (and it sometimes does - just didn't think it was related) the car doesn't even turn over, there is no clicking or sounds whatsoever, so I'm not inclined to think that's a filter problem - or even related to the problem originally described.
posted by whatisish at 9:57 AM on November 11, 2014


This happened to me this past August in a 2010 Kia, same symptom - no real power on acceleration, just a very slow increase. Stopped after I shut the car off, but happened again after a short drive. I was on a road trip at the time and took it immediately to the first road-side mechanic I came across. He cleared the codes then used the ODBII computer to diagnosed a fouled spark plug was causing a misfire and was what was putting the car into limp mode. We got a new set of plugs installed and have not had a problem since that day. No limp mode indicator on the dash, just a check engine light.
posted by Mahogne at 10:36 AM on November 11, 2014


If there's no check-engine light, your transmission may be slipping. Depending on the issue, it may not trigger a check-engine light like a clogged injector or fouled fuel filter would.

First thing to do would be to check the transmission fluid levels, and check to see if it's burnt. (Will smell something like burnt toast and appear very dark or black.) If it's low, top it up, if it's burnt, change it, and keep an eye out for metal shavings. In either event, it may be indicative of a more serious problem - fluid leak or overheating - that will need to be taken care of as well.
posted by Slap*Happy at 10:44 AM on November 12, 2014


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